Scientists shed new light on role of viruses in coral bleaching

Scientists at Oregon State University have shown that viral infection is sometimes involved in coral bleaching -- the breakdown of the symbiotic relationship between corals and the algae they rely on for energy.

Viral infection is involved in coral bleaching -- the breakdown of the relationship between corals and algae. Photo: OSU

The research is leading to a new understanding of the factors behind coral health, crucial to efforts in saving Earth's embattled reefs.

Between 2014 and 2017, more than 75% experienced bleaching-level heat stress and 30% suffered mortality-level stress.

The planet's largest and most significant structures of biological origin, coral reefs are found in less than 1% of the oceans but are home to nearly one-quarter of all known marine species.

Since their first appearance 425 million years ago, corals have branched into more than 1,500 species. A complex composition of dinoflagellates, fungi, bacteria, archaea and viruses make up the coral microbiome; shifts in microbiome composition are connected to changes in coral health.

To better understand how viruses contribute to making corals healthy or unhealthy, scientists Adriana Messyasz and Rebecca Vega Thurber led a project that compared the viral metagenomes of coral colony pairs during a 2016 bleaching event in Mo'orea, French Polynesia. The region is home to the NSF-supported Mo'orea Coral Reef Long-Term Ecological Research site.

Also known as environmental genomics, metagenomics refers to studying genetic material recovered directly from environmental samples, in this case samples taken from a coral reef.

The scientists collected bleached and non-bleached pairs of corals to determine whether the viruses were alike or different. The bleached and non-bleached corals shared nearly identical environmental conditions.

"After analyzing the viral metagenomes of each pair, we found that bleached corals had a higher abundance of eukaryotic viral sequences, and non-bleached corals had a higher abundance of bacteriophage sequences," Messyasz said. "That gave us the first quantitative evidence of a shift in viral assemblages between coral bleaching states." (National Science Foundation)

YOU MAY ALSO LIKE

‘Happy ending effect’ can bias future decisions

Humans are hard-wired to prefer experiences that end well, and the influence of previous experience declines the longer ago it happened.

Physicists observe room-temperature superconductivity

Researchers at the University of Rochester and the University of Las Vegas, Nevada, have made a breakthrough in the long sought-after quest for a room-temperature superconductor, which they call the "holy grail" of energy efficiency.

Researchers are Juicing Alfalfa as a Next-Generation Aquafeed

Cows and horses aren't the only fans of alfalfa. Yellow perch like it, too. That's what Agricultural Research Service (ARS) scientists and their collaborators concluded when they fed the fish pellets made with a protein concentrate from the legume crop's protein-rich leaves.

Dried, pressed plants predict climate future

Dried and pressed plants are being matched with artificial intelligence to help researchers predict climate change impacts.

Climate patterns linked in Amazon, North and South America

Researchers used newly developed tree-ring chronology from the Amazon River basin.

Scientists turn pineapple waste into high-value aerogels

Harvesting of pineapples, a widely grown tropical fruit, leaves behind tons of agricultural residues which are usually burned or left to rot, creating undesirable greenhouse gases.